A PROPOSED MECHANISM FOR THE EFFECT OF DIFFERENT DIETARY FATS ON SOME ASPECTS OF CHOLESTEROL METABOLISM

1962 ◽  
Vol 40 (8) ◽  
pp. 1091-1100 ◽  
Author(s):  
J. A. Wilkens ◽  
H. de Wit ◽  
B. Bronte-Stewart
Keyword(s):  
Fatty Acids ◽  
Serum Cholesterol ◽  
Cholesterol Metabolism ◽  
Dietary Cholesterol ◽  
Serum Levels ◽  
High Serum ◽  
Dietary Fats ◽  
Cholesterol Concentration ◽  
Serum Cholesterol Concentration ◽  
Endogenous Cholesterol

To explain the effect of dietary cholesterol and different fats on serum cholesterol concentration a hypothesis is proposed according to which the condition for the absorption of dietary cholesterol is its state of solution in dietary or endogenous fats. Dietary fats, free from cholesterol, exert their effect on serum cholesterol concentration by causing reabsorption of biliary or endogenous cholesterol. To test this hypothesis the solubility of cholesterol in a number of natural and modified triglyceride fats at 37 °C was determined and found to correlate with the effects of these fats on the serum cholesterol concentration of rats and man. Relatively high solubilities were associated with high serum levels and vice versa. Artificial modification of both unsaponifiable matter and fatty acids of triglyceride oils was found to alter the solubility of cholesterol in these oils. The solubility concept is discussed as a possible mechanism underlying the effect of different dietary fats on serum cholesterol concentration and other aspects of cholesterol metabolism such as absorption, excretion, and liver synthesis.

A PROPOSED MECHANISM FOR THE EFFECT OF DIFFERENT DIETARY FATS ON SOME ASPECTS OF CHOLESTEROL METABOLISM

1962 ◽  
Vol 40 (1) ◽  
pp. 1091-1100 ◽  
Author(s):  
J. A. Wilkens ◽  
H. de Wit ◽  
B. Bronte-Stewart
Keyword(s):  
Fatty Acids ◽  
Serum Cholesterol ◽  
Cholesterol Metabolism ◽  
Dietary Cholesterol ◽  
Serum Levels ◽  
High Serum ◽  
Dietary Fats ◽  
Cholesterol Concentration ◽  
Serum Cholesterol Concentration ◽  
Endogenous Cholesterol

To explain the effect of dietary cholesterol and different fats on serum cholesterol concentration a hypothesis is proposed according to which the condition for the absorption of dietary cholesterol is its state of solution in dietary or endogenous fats. Dietary fats, free from cholesterol, exert their effect on serum cholesterol concentration by causing reabsorption of biliary or endogenous cholesterol. To test this hypothesis the solubility of cholesterol in a number of natural and modified triglyceride fats at 37 °C was determined and found to correlate with the effects of these fats on the serum cholesterol concentration of rats and man. Relatively high solubilities were associated with high serum levels and vice versa. Artificial modification of both unsaponifiable matter and fatty acids of triglyceride oils was found to alter the solubility of cholesterol in these oils. The solubility concept is discussed as a possible mechanism underlying the effect of different dietary fats on serum cholesterol concentration and other aspects of cholesterol metabolism such as absorption, excretion, and liver synthesis.

Effects of Diet on Blood Lipids In Man

1955 ◽  
Vol 1 (1) ◽  
pp. 34-52 ◽  
Author(s):  
Ancel Keys ◽  
Joseph T Anderson ◽  
Flaminio Fidanza ◽  
Margaret Haney Keys ◽  
Bengt Swahn
Keyword(s):  
Serum Cholesterol ◽  
Dietary Fat ◽  
Blood Lipids ◽  
Dietary Cholesterol ◽  
Average Concentration ◽  
Cholesterol Concentration ◽  
Calorie Intake ◽  
Serum Cholesterol Concentration ◽  
Per Se ◽  
Total Fat

Abstract 1. Lipids exist in the blood serum as emulsions ("chylomicrons") and as solutions of lipoprotein containing proteins, cholesterol, and other lipids. Interest in relation to atherosclerosis is centered on the cholesterol and the beta lipoproteins which contain most of the cholesterol. 2. The diet influences the blood lipids in man and animals but great quantitative differences between species makes it essential to study man himself to discover the effects of the diet on the blood lipids in man. 3. The amount of lipid in the chylomicron form in the serum is practically independent of the concentration of cholesterol and lipoproteins in the serum. The correlation between the concentrations of alpha and beta lipoproteins is very low. 4. Experiments on man show that dietary cholesterol per Se, even in large amount, has no important influence on the serum cholesterol concentration but that the latter is markedly affected by the total fat content of the diet. 5. Calorie intake per se has little influence on the blood lipids. Such effect as it has may be secondary to fat metabolism differences commonly associated with differences in calorie intakes. 6. Studies on population samples of healthy men show a marked direct relationship between the content or proportion of fat in the diet on the one hand and the concentration of total cholesterol and of beta lipoproteins in the serum on the other. The effect of the diet tends to be greater in middle-aged men than in younger men. 7. The average concentration of cholesterol in the serum of men in areas where the diets are very high in fats (of the order of 40 per cent of calories), is 25 to 50 per cent greater than the average in areas where the diets are low in fats (of the order of 20 per cent, or less, of calories). 8. A significant effect of dietary fat level on the serum cholesterol concentration is evident in man in a few weeks on a changed diet. The effect tends to increase very slowly with time thereafter and it is most pronounced when comparison is made between populations habitually subsisting on different diets. 9. It is not known how the dietary fat intake exerts its controlling influence on the blood lipids of man but the mechanisms must be complex.

Effect of Nicotinic Acid on Cholesterol Metabolism in Monkeys

1974 ◽  
Vol 46 (4) ◽  
pp. 527-538
Author(s):  
Amany A. Magide ◽  
N. B. Myant
Keyword(s):  
Nicotinic Acid ◽  
Serum Cholesterol ◽  
Cholesterol Metabolism ◽  
Specific Radioactivity ◽  
Cholesterol Concentration ◽  
Moderate Degree ◽  
Serum Free Fatty Acid ◽  
Faecal Excretion ◽  
Serum Cholesterol Concentration ◽  
Endogenous Steroids

1. Single subcutaneous injections of nicotinic acid lowered the serum free fatty acid and triglyceride concentration in two non-fasting Rhesus monkeys. 2. Injections of nicotinic acid repeated daily for 2–4 weeks led to a substantial fall in serum cholesterol concentration, comparable with that obtained in humans given therapeutic doses of nicotinic acid by mouth. 3. The fall in serum cholesterol concentration was accompanied by a decrease in hepatic synthesis of cholesterol but there was no change in the faecal excretion of endogenous steroids. 4. The rate of synthesis of cholesterol, estimated from the faecal excretion of endogenous steroids and from the serum specific radioactivity curve, was such that a moderate degree of inhibition would have accounted for the observed decrease in the amount of circulating cholesterol during nicotinic acid treatment.

Endogenous excretion and capacity to absorb dietary cholesterol in the chicken

1959 ◽  
Vol 197 (6) ◽  
pp. 1341-1344 ◽  
Author(s):  
H. M. Janecek ◽  
R. Suzuki ◽  
A. C. Ivy
Keyword(s):  
Serum Cholesterol ◽  
Dietary Cholesterol ◽  
Cottonseed Oil ◽  
Cholesterol Concentration ◽  
Fecal Excretion ◽  
Average Weight ◽  
White Leghorn ◽  
Serum Cholesterol Concentration

The endogenous fecal elimination of cholesterol in 12 1900-gm (av.) White Leghorn cockerels 14–16 weeks of age kept on a cholesterol-free diet containing 3% cottonseed oil was found to be 20 mg/day, when corrected for the intake of phytosterol. The intestinal capacity to absorb dietary cholesterol under these conditions was found to be 210 mg/day in 12 2100-gm (av.) cockerels 16–21 weeks of age when fed 916, 920 or 1145 mg/day each day for 7 days. The capacity to absorb was the same when the average weight was 1900 gm and 2400 gm, indicating that the intestine had become mature when the cockerels weighed an average of 1900 gm. The serum cholesterol concentration was significantly increased after the ingestion of 85 mg of cholesterol a day for 7 days; this amount was four times greater than the endogenous fecal excretion.

scholarly journals DIETARY FAT AND HYPERCHOLESTEREMIA IN THE CEBUS MONKEY

1957 ◽  
Vol 106 (5) ◽  
pp. 727-742 ◽  
Author(s):  
Oscar W. Portman ◽  
Leonardo Sinisterra
Keyword(s):  
Fatty Acids ◽  
Total Cholesterol ◽  
Serum Cholesterol ◽  
Corn Oil ◽  
Cholesterol Metabolism ◽  
Specific Activity ◽  
Cholesterol Absorption ◽  
Dietary Fats ◽  
Intragastric Administration ◽  
Cebus Monkey

A series of studies of cholesterol metabolism in the Cebus monkey were carried out in an attempt to understand the mechanisms responsible for the great differences in serum cholesterol levels when different dietary fats were used. Three groups of monkeys, one fed diets including 45 per cent of calories as corn oil, a second corn oil plus cholesterol (0.1 gm./100 calories), and a third lard plus cholesterol for 5 months (mean serum cholesterol values were 237, 268, and 601 mg. per cent, respectively) were injected with emulsions of cholesterol-4-C14. The mean biological half-lives for the disappearance of serum radiocholesterol were 8.8, 8.4, and 6.6 days respectively. Esterification of radiocholesterol as measured by equilibration of specific activities of serum-free cholesterol and total cholesterol was delayed in the monkeys fed lard plus cholesterol. When cholesterol-4-C-14-stearate was given intravenously to a series of monkeys, an erratic non-exponential biological decay curve resulted. Specific activity for free serum cholesterol was greater than that for total cholesterol within 1 hour after the injection. After 7 months on experimental diets including corn oil with added cholesterol and lard with added cholesterol the levels of lipides in most tissues were not different for the two dietary groups, nor were they appreciably elevated above previous control figures for monkeys not fed cholesterol. Total lipide levels in the adrenals of monkeys fed corn oil were twice those of monkeys fed lard. Monkeys were fasted before and after intragastric administration of cholesterol-4-C14 in small formula meals including various fats and fatty acids. The disappearance of total cholesterol from the serum consisted of a rapid followed by a slow exponential function. The type of fat and fatty acid appeared to influence the rate of disappearance of radiocholesterol. There was a broad range of apparent activity of the different fats and fatty acids in promoting cholesterol absorption.

THE EFFECT OF DIET, AGE, AND SEX ON CHOLESTEROL METABOLISM IN WHITE LEGHORN CHICKENS

1961 ◽  
Vol 39 (11) ◽  
pp. 1705-1715 ◽  
Author(s):  
J. D. Wood ◽  
J. Biely ◽  
J. E. Topliff
Keyword(s):  
Serum Cholesterol ◽  
Corn Oil ◽  
Cholesterol Metabolism ◽  
Control Diet ◽  
Dietary Cholesterol ◽  
Normal Serum ◽  
Cholesterol Concentration ◽  
Cholesterol Levels ◽  
Yolk Cholesterol ◽  
Age And Sex

The cholesterol metabolism of chickens differed in birds of different age and sex. The normal serum cholesterol levels were higher in females than in males and higher in 1-week-old chicks than in mature birds of the same sex. Laying hens were less susceptible to hypercholesterolemia induced by dietary cholesterol than were mature cockerels or young chicks of either sex. Corn oil tended to increase the degree of hypercholesterolemia in all cholesterol-fed birds except young cockerels. A vitamin-A-rich oil, dogfish liver oil, decreased the rise in serum cholesterol level in cholesterol-fed chicks of both sexes, but in mature birds it produced the opposite effect. The addition of 1% cholesterol to the control diet of hens increased the yolk cholesterol concentration of eggs laid by the birds and this increase in concentration was greatly enhanced if 10% corn oil was also present in the diet.

Sign in / Sign up

Export Citation Format

Share Document